Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds provenance ('derived from recent crewed SpaceX launches') and enumerates return fields, but says nothing about pagination, ordering, freshness lag, or limits beyond what the schema documents.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the core scope, with no filler. The closing provenance sentence slightly overlaps the opening scope statement, keeping it just short of a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so the listed return fields are a bonus rather than a burden, and the annotations plus schema cover the rest. For a simple parameterless read tool this is nearly complete; only usage/routing context is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter (limit) and schema description coverage is 100%, so the default of 20 and max of 50 are already fully documented. The description adds no syntax or formatting detail beyond the schema, which matches the baseline 3 for a fully-covered single param.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: 'List astronauts who have flown (or are assigned to) SpaceX Crew Dragon missions.' The domain is narrow enough to separate it from launch/rocket siblings like get_past_launches or get_rockets, though it never names an alternative explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the tightly scoped subject matter, but there is no explicit when-to-use, when-not-to-use, or sibling routing guidance. An agent can infer this is the crew-lookup tool, but the description doesn't confirm it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.